The assignee of the present invention designs and manufactures spacecraft for, inter alia, communications and broadcast services. Many satellite services are provided from spacecraft in geosynchronous orbit (GEO), an orbit having a semi-major axis of 42,164 kilometers and an orbital period of one sidereal day of (23 hr. 56 min. 4 seconds, the period of rotation of Earth in inertial space). Because longitudes (“slots”) at which spacecraft may be stationed in GEO (i.e., available locations on the GEO “arc”) are limited, there is a strong market demand to maximize the revenue generated from each slot. As a result, many satellites disposed in GEO have grown increasingly larger, more complex and expensive, with satellite operators demanding higher power, and more payload throughput, and multi-payload spacecraft. The cost to acquire such a satellite, including launch and insurance, can represent a substantial barrier to entry for those wishing to provide space based services.
Launch vehicle compatibility is a second requirement faced by a spacecraft designer. The increased performance requirements are only advantageously met if compatibility with conventional, commercially available launch vehicles is maintained. Accordingly, a spacecraft, as configured for launch, is desirably made compatible with fairing envelope constraints of such launch vehicles as, for example, Ariane V, Atlas XEPF, Proton, and Falcon 9. As a result, it is very often a requirement to reconfigure a spacecraft from a launch configuration to an on-orbit configuration. Some techniques related to this requirement are disclosed in U.S. Pat. Nos. 5,644,322, 6,448,940, 8,789,796 and 8,448,902, assigned to the assignee of the present disclosure, and in U.S. patent application Ser. Nos. 14/642,486 and 15/160,258, assigned to the assignee of the present disclosure, the disclosures of which are hereby incorporated by reference into the present disclosure in their entirety for all purposes.
Modern GEO spacecraft are also required to reliably operate on-orbit for 15 years or more, however changes in payload technology and market demands may result in obsolescence of a payload well before the spacecraft bus equipment reaches end-of-life.